Besides some of @ahcorde 's inline comments, we will also need to have PRs to the rest of the ROS 2 core to use the .hpp files instead of the .h ones. Also, this is a large enough change that once we are ready to merge it, we should probably send a message to https://discourse.ros.org letting people know that we've done this.

Yeah I figured we would have to extend PRs to various libraries, I have one linked from rviz, but I haven't found anymore, I'll have to do some digging around to find out if I've missed any more of the core ones. As far as the copyrighting goes, I believe those inline comments were the missing piece, I've submitted a fix.

Updated downstream packages:

• Fix Deprecated tf2 headers rviz#1289
• Deprecating tf2 C Headers ros2_documentation#4828
• Deprecating tf2 C Headers cartographer_ros#75
• Deprecating tf2 C Headers ros/geometry#244
• Deprecating tf2 C Headers ros/geometry2#573
• Deprecate tf2 C Headers ros/geometry_tutorials#87
• Deprecate c headers ros-perception/imu_pipeline#25
• Deprecating tf2 C Headers ros-perception/laser_geometry#98
• Deprecate c headers ros-perception/laser_filters#206
• Deprecating tf2 C Headers ros-perception/image_pipeline#1039
• Deprecating tf2 C Headers ros-perception/perception_pcl#469
• Deprecating tf2 C Headers ros-controls/ros2_controllers#1325
• Deprecating tf2 C Headers ros-navigation/navigation2#4732
• Deprecate tf2 C Headers ros-industrial/industrial_training#420

These were all the repositories that I could find, within the core ROS organizations, in which tf2 was utilized. There are likely thousands of repositories which are going to have warnings, which are warnings as to not break API, but I certainly wouldn't mind making a general PSA.

Would it make sense to provide .hpp files for all active distros? With as only content the include of the .h file.

This would mean all projects that do not have a branch per release can use this syntax already. Preventing ugly statements like this everywhere: https://github.com/autowarefoundation/autoware.universe/blob/9bd0f77c255edcff129ff08d190a5fdd8c45b6dc/localization/yabloc/yabloc_common/src/pub_sub.cpp#L18

For rolling we can keep the deprecation flag, not for older distros.

Yeah I don't see much of a compile downside, just a weirder file structure for older distributions. I assume we would just never phase out the .h files unlike the rolling branch in which we can remove them in L-Turtle. I would be able to add this "backport" later today if that's something we agree on.

Also there already seems to be some consensus in the other core repositories:

• Deprecating tf2 C Headers ros-perception/perception_pcl#469

we should create backwards compatibilty headers that emit compile warnings so users have time to migrate to the new headers.

• Deprecating tf2 C Headers ros-controls/ros2_controllers#1325

Can you add conditioning in the code so that from rolling on it uses the .hpp, and in the prior versions it uses the .h version?

@ahcorde Could you please try to rerun CI?

included PRs: geometry2, laser_geometry, RViz2 and interactive_markers

• Linux
• Linux-aarch64
• Linux-rhel
• Windows

• Linux
• Linux-aarch64
• Linux-rhel
• Windows

Iron I guess?

Can you do humble if it's not too much work?

What's the story on humble? Our work environment is now broken from the docker images supplied from ros:humble-ros-core.

Currently, in this broken state, we have the following installed.

• ros-humble-tf2 version 0.25.9-1jammy.20241128.023902
• ros-humble-tf2-eigen version 0.25.11-1jammy.20250114.170617

In tf2_eigen.hpp, it includes "tf2/convert.hpp".

Then, the files that exist:

$ ls /opt/ros/humble/include/tf2/tf2/ -1
LinearMath
buffer_core.h
buffer_core_interface.h
convert.h
exceptions.h
impl
time.h
time_cache.h
transform_datatypes.h
transform_storage.h
utils.h
visibility_control.h

Where's the deprecation period and how did this get all the way through the build farm into a docker image with debians that don't work together. Why isn't tf2-eigen expressing a minimum version on tf2 so it fails at configure time?

Sorry to be blunt, but this is just frustrating.

• ros-humble-tf2 version 0.25.9-1jammy.20241128.023902

• ros-humble-tf2-eigen version 0.25.11-1jammy.20250114.170617

These aren't the same versions, which is why you are having trouble here. The debians that are released should all match as 0.25.11; the fact that they aren't probably means your local scripts are missing an apt-get update somewhere (i.e. it is using a cached layer with tf2, and a new layer with tf2_eigen).

Thanks. If there's any changes we could do to ensure that we fail at configure time rather than build time, I'd be happy to contribute those.